[Myopia, a growing health problem]

- Myopia is the eye disorder with the most rapid increase in prevalence worldwide. It develops in childhood, with a peak incidence between the ages of 13 to 15 years. - Especially high myopia, i.e. a refractive error of -6 diopters or more, increases the risk of permanent visual impairment during adulthood due to structural abnormalities of the retina and optic nerve.- The cause of myopia is complex. Lifestyle factors in childhood, such as limited time spent outdoors and close work - such as reading and smartphone usage - are risk factors. Furthermore, genetic studies have revealed more than 100 factors associated with the development of myopia. - Pharmacological and optical interventions to inhibit myopia progression are increasingly applied. The use of atropine eye drops in children and has shown to be an effective treatment.

Kinetics of first polar body extrusion and the effect of time of stripping of the cumulus and time of insemination on developmental competence of bovine oocytes

Kinetics of extrusion of the first polar body was examined as well as the effect of the time of stripping of the cumulus cells on this kinetics. In addition, the effects of time of stripping and time of insemination on developmental competence of the oocytes, as evaluated by the percentage of morulae and blastocysts, were studied. Polar body extrusion occurred in 80% of the oocytes between 12 and 18 h after the onset of maturation. The remainder of the oocytes did not extrude a polar body at all. Stripping of the cumulus at 12 h after the onset of maturation delayed polar body extrusion significantly by about 1 h. No significant differences were found in the percentage of oocytes that could be fertilized, and the percentage of oocytes that cleaved and developed to the morula and blastocyst stages, between oocytes that were stripped free of cumulus and inseminated at either 16 or 20 h after onset maturation. Oocytes that had extruded a polar body at either 16 or 20 h after onset maturation showed significantly higher percentages of cleavage and development than oocytes that had not extruded a polar body at those time points. However, the percentage of oocytes that could be fertilized was not affected.

Effects of neutralization of pregnant mares' serum gonadotrophin (PMSG) shortly before or at the preovulatory LH surge in PMSG-superovulated heifers on follicular function and development

Normally cyclic heifers (n = 34) received 2500 iu pregnant mares' serum gonadotrophin (PMSG) i.m. at day 10 of oestrus, and 15 mg prostaglandin (PG) i.m. at day 12. Thereafter, a monoclonal antibody against PMSG was administered i.v. before (n = 24), at (n = 6) or shortly after (n = 4) the preovulatory LH surge. Peripheral blood concentrations of LH and oestradiol were compared; follicular development was monitored by daily ultrasound scanning; and the numbers of preovulatory-sized follicles and ovulations were counted 96 h after injection of PG following death. Anti-PMSG treatment before the LH surge inhibited the LH surge in 16 heifers (67%). In these heifers, the initial increase in oestradiol concentration upon PMSG stimulation to 167.5 +/- 35.0 pmol l-1 was terminated immediately after anti-PMSG treatment and decreased rapidly to basal values, while the number of preovulatory-sized follicles remained constant until 68 h after PG injection; on average 0.4 +/- 0.1 ovulations were counted. In the remaining eight heifers, five animals showed an immediate, but temporary, 20-60% drop in oestradiol concentration after anti-PMSG treatment. In all eight heifers 25% of the preovulatory-sized follicles ovulated. Treatment with anti-PMSG at or shortly after the LH surge did not affect the pattern of oestradiol concentration, but a significantly higher ovulation rate was observed in the animals treated shortly after the LH surge: 20.3 +/- 2.6 versus 6.3 +/- 2.3 in animals treated at the LH surge, which corresponded to 76% and 24% of the preovulatory-sized follicles monitored shortly before the period of multiple ovulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Generation of transgenic dairy cattle using 'in vitro' embryo production

We have combined gene transfer, by microinjection, with 'in vitro' embryo production technology, enabling us to carry out non-surgical transfer, to recipient cows, of microinjected embryos that have been cultured from immature oocytes. Using this approach, we have established 21 pregnancies from which 19 calves were born. Southern blot analysis proved that in two cases the microinjected DNA had been integrated in the host genome.